A sexual selection model of schizophrenia

Schizophrenia is a mental disorder marked by an evolutionarily puzzling combination of high heritability, reduced reproductive success, and a remarkably stable prevalence. Recently, it has been proposed that sexual selection may be crucially involved in the evolution of schizophrenia. In the sexual selection model (SSM) of schizophrenia and schizotypy, schizophrenia represents the negative extreme of a sexually selected indicator of genetic fitness and condition. Schizotypal personality traits are hypothesized to increase the sensitivity of the fitness indicator, thus conferring mating advantages on high-fitness individuals but increasing the risk of schizophrenia in low-fitness individuals; the advantages of successful schzotypy would be mediated by enhanced courtship-related traits such as verbal creativity. Thus, schizotypy-increasing alleles would be maintained by sexual selection, and could be selectively neutral or even beneficial, at least in some populations. However, most empirical studies find that the reduction in fertility experienced by schizophrenic patients is not compensated for by increased fertility in their unaffected relatives. This finding has been interpreted as indicating strong negative selection on schizotypy-increasing alleles, and providing evidence against sexual selection on schizotypy.
That is from Marco Del Giudice and for the pointer I thank Harpersnotes.

For the first time, scientists have pinned down a molecular process in the brain that helps to trigger schizophrenia. The researchers involved in the landmark study, which was published Wednesday in the journal Nature, say the discovery of this new genetic pathway likely reveals what goes wrong neurologically in a young person diagnosed with the devastating disorder.

Total fertility rates, which can be defined as the average number of children born to a woman who survives her reproductive years (aged 15-49), have decreased globally by about half since 1960.
This has drastically shaped today’s global economy, but a continued decline could have much more severe long-term consequences. If the world has too many elderly dependents and not enough workers, the burden on economic growth will be difficult to overcome.

VANCOUVER — A sperm donor billed as a genius turned out to be a convicted felon with serious mental health problems, according to lawsuits filed in B.C. Supreme Court.
The man who donated sperm to two Vancouver families so that they could have children through artificial insemination was falsely characterized and improperly screened.
The plaintiffs, who are identified only by initials, are suing Xytex Corp., an Atlanta-based sperm bank and Genesis Fertility Centre Inc. in Vancouver.

While our personalities are correlated with whether we are liberal or conservative, it seems that neither one of these causes the other. Instead, their correlation is caused by something else that causes both, and that is caused in part by genetics:

Muhammad Chaudhary came nowhere near passing his Canadian-citizenship knowledge test, scoring two out of 20 on the questions about Canada’s geography, history and political system. He was denied citizenship as a result.
But a Federal Court judge in Calgary has overturned that decision, citing a surprising reason: there is evidence his mental illness — schizophrenia — makes it all but impossible for him to retain such facts and figures.